Increasingly, food retailers and supermarkets in particular require suppliers to provide packs of sliced food products of standard weights. Labelling regulations may permit some deviation from the standard weights indicated on packs but only within narrow tolerances.
It is therefore desirable for food suppliers to aim to provide packs which just meet the associated weight requirements, minimising the extent to which any minimum requirement is exceeded. Any such excess food product included in a pack is often referred to as “give-away”.
In view of the pressure to just satisfy a minimum requirement, groups of slices are occasionally generated by a slicing machine which are slightly below this minimum threshold. In known processing arrangements, these “under-weight” groups are diverted out of the path to the packaging process and to a separate station, sometimes referred to as the “make-weight” station. An operator at the make-weight station adds an additional slice to each under-weight group of slices and then returns the group made up to an acceptable weight with the additional slice into the path to the packaging process.
This process tends to increase give-away, as under-weight packs are likely to fall short of the minimum threshold by an amount less than the weight of an entire additional slice. For example, a slice of bacon may typically weigh 20 g. If an under-weight group of slices only falls short by 2 g, the under-weight group together with an additional slice created at the make-weight station will include a give-away of 18 g. Given the large number of under-weight packs likely to be generated by a processor having a high throughput of food packs, the cumulative give-away is substantial and therefore costly.
A food slicing machine is typically configured to cut each slice from a log of food product according to the current value of a slice size parameter, often referred to as the slicer “set point”. If this parameter is set too low, the make-weight station becomes inundated with under-weight groups of slices and the operator at the make-weight station can become overwhelmed. If the parameter is set too high, the amount of give-away increases, making the process less cost efficient.
The physical properties of food products can vary in stability depending on the type of food product to be sliced. A relatively homogeneous product such as cheese has reasonably consistent properties, whereas the properties of a less consistent, naturally formed product such as bacon can vary significantly depending on a number of variables, such as the lean-to-fat ratio, the temperature of the food product, its brine content and the like. When slicing this type of product, the optimum set point can vary from day to day and during the course of each day. Careful monitoring and control of the set point is therefore desirable to maximise the efficiency of the system during operation.